Field of the Invention
The present invention relates to an imaging apparatus such as a digital still camera and a digital video camera and an imaging method.
Description of the Related Art
A time-varying subject, for example, a progress of a building under construction and a seasonally-varying landscape is shot in chronological order and the images of such a time-varying subject are compared by using an imaging apparatus such as a digital still camera. In this case, it is preferable to chronologically compare images shot at the same angle and distance. However, it is difficult to locate an imaging apparatus in the same position at all times and it is also difficult to shoot a subject at the same angle and distance at all times since the angle is determined based on feeling of a photographer.
An imaging apparatus that previously shoots an image and superimposes the previously shot image and a monitoring subject image to be displayed for determining an angle of shooting is disclosed by Patent Document 1 (Japanese Patent Publication No. 4059241). When taking a ceremonial picture with this imaging apparatus, a subject is previously shot for previously determining a composition. After that, it can be requested to the third person to shoot a picture at an angle the same as that of the previous shooting. The invention disclosed by Patent Document 1 aims to achieve actual shooting consistent with an intention of a client regardless of a shooting technique of the third person or a shooting interval.
However, the invention disclosed by Patent Document 1 uses an image shot just before actual shooting for determining the angle, and does not use past image data for current shooting. Since the previously shot image is overwritten to be deleted after actual shooting, the shooting cannot be performed many times with the same previously shot image. For this reason, an already shot image cannot be compared with a subject image to be photographed, and a time-varying subject cannot be shot at an angle the same as that of the past image.